RocketMQ重试策略及与Springboot整合

注：基础请参考上一篇文章RocketMQ简介与安装及入门

1. 重试策略

在消息的发送和消费过程中，都有可能出现错误，如网络异常等，出现了错误就需要进行错误重试，这种消息的重试需要分2种，分别是producer端重试和consumer端重试。

1.1 producer端重试

生产者端的消息失败，也就是Producer往MQ上发消息没有发送成功，比如网络抖动导致生产者发送消息到MQ失败。

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.common.message.Message;
import org.apache.rocketmq.remoting.common.RemotingHelper;
public class SyncProducer {public static void main(String[] args) throws Exception {DefaultMQProducer producer = new DefaultMQProducer("Hello");producer.setNamesrvAddr("192.16.55.185:9876");//消息发送失败时，重试3次producer.setRetryTimesWhenSendFailed(3);producer.start();String msgStr = "用户A发送消息给用户B";Message msg = new Message("hello_topic","SEND_MSG",msgStr.getBytes(RemotingHelper.DEFAULT_CHARSET));// 发送消息,并且指定超时时间SendResult sendResult = producer.send(msg, 1000);System.out.println("消息状态：" + sendResult.getSendStatus());System.out.println("消息id：" + sendResult.getMsgId());System.out.println("消息queue：" + sendResult.getMessageQueue());System.out.println("消息offset：" + sendResult.getQueueOffset());System.out.println(sendResult);producer.shutdown();}
}

1.2 consumer端重试

消费者端的失败，分为2种情况，一个是exception，一个是timeout。

1.2.1 exception

消息正常的到了消费者，结果消费者发生异常，处理失败了。例如反序列化失败，消息数据本身无法处理（例如话费充值，当前消息的手机号被注销，无法充值）等。
消息的状态：

package org.apache.rocketmq.client.consumer.listener;
public enum ConsumeConcurrentlyStatus {/*** Success consumption*/CONSUME_SUCCESS,/*** Failure consumption,later try to consume*/RECONSUME_LATER;
}

可以看到，消息的状态分为成功或者失败。如果返回的状态为失败会怎么样呢？
在启动broker的日志中可以看到这样的信息：

INFO main - messageDelayLevel=1s 5s 10s 30s 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 20m 30m 1h
2h

这个表示了，如果消息消费失败，那么消息将会在1s、5s、10s后重试，一直到2h后不再重试。其实，有些时候并不需要重试这么多次，一般重试3~5次即可。这个时候就可以通过msg.getReconsumeTimes()获取重试次数进行控制。

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.client.exception.MQClientException;
import org.apache.rocketmq.common.message.MessageExt;
import org.apache.rocketmq.common.protocol.heartbeat.MessageModel;
import java.io.UnsupportedEncodingException;
import java.util.List;
public class ConsumerDemo {public static void main(String[] args) throws Exception {DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("Hello");consumer.setNamesrvAddr("192.16.55.185:9876");// 订阅topic，接收此Topic下的所有消息consumer.subscribe("my-topic", "*");consumer.registerMessageListener(new MessageListenerConcurrently() {@Overridepublic ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs,
ConsumeConcurrentlyContext context) {for (MessageExt msg : msgs) {try {System.out.println(new String(msg.getBody(), "UTF-8"));} catch (UnsupportedEncodingException e) {e.printStackTrace();}}System.out.println("收到消息->" + msgs);if(msgs.get(0).getReconsumeTimes() >= 3){// 重试3次后，不再进行重试return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;}return ConsumeConcurrentlyStatus.RECONSUME_LATER;}});consumer.start();}
}

1.2.2 timeout

比如由于网络原因导致消息压根就没有从MQ到消费者上，那么在RocketMQ内部会不断的尝试发送这条消息，直至发送成功为止！也就是说，服务端没有接收到消息的反馈，既不是成功也不是失败，这个时候定义为超时。

2 RocketMQ的集群

2.1 集群模式

在RocketMQ中，集群的部署模式是比较多的，有以下几种：

单个Master
这种方式风险较大，一旦Broker重启或者宕机时，会导致整个服务不可用，不建议线上环境使用。
Master模式
一个集群无Slave，全是Master，例如2个Master或者3个Master。单台机器宕机期间，这台机器上未被消费的消息在机器恢复之前不可订阅，消息实时性会受到影响。
多Master多Slave模式，异步复制。每个Master配置一个Slave，有多对Master-Slave，HA采用异步复制方式，主备有短暂消息延迟，毫秒级。
优点：即使磁盘损坏，消息丢失的非常少，且消息实时性不会受影响，因为Master宕机后，消费者仍然可以从Slave消费，此过程对应用透明，不需要人工干预。性能同多Master模式几乎一样。
缺点：Master宕机，磁盘损坏情况，会丢失少量消息。
多Master多Slave模式，同步双写。每个Master配置一个Slave，有多对Master-Slave，HA采用同步双写方式，主备都写成功，向应用返回成功。
优点：数据与服务都无单点，Master宕机情况下，消息无延迟，服务可用性与数据可用性都非常高。
缺点：性能比异步复制模式略低，大约低10%左右。

2.2 搭建2m2s集群

下面通过docker搭建2master+2slave的集群。

#创建2个master
#nameserver1
docker create -p 9876:9876 --name rmqserver01 \
-e "JAVA_OPT_EXT=-server -Xms128m -Xmx128m -Xmn128m" \
-e "JAVA_OPTS=-Duser.home=/opt" \
-v /haoke/rmq/rmqserver01/logs:/opt/logs \
-v /haoke/rmq/rmqserver01/store:/opt/store \
foxiswho/rocketmq:server-4.5.2
#nameserver2
docker create -p 9877:9876 --name rmqserver02 \
-e "JAVA_OPT_EXT=-server -Xms128m -Xmx128m -Xmn128m" \
-e "JAVA_OPTS=-Duser.home=/opt" \
-v /haoke/rmq/rmqserver02/logs:/opt/logs \
-v /haoke/rmq/rmqserver02/store:/opt/store \
foxiswho/rocketmq:server-4.5.2#创建第1个master broker
#master broker01
docker create --net host --name rmqbroker01 \
-e "JAVA_OPTS=-Duser.home=/opt" \
-e "JAVA_OPT_EXT=-server -Xms128m -Xmx128m -Xmn128m" \
-v /haoke/rmq/rmqbroker01/conf/broker.conf:/etc/rocketmq/broker.conf \
-v /haoke/rmq/rmqbroker01/logs:/opt/logs \
-v /haoke/rmq/rmqbroker01/store:/opt/store \
foxiswho/rocketmq:broker-4.5.2#配置
namesrvAddr=192.16.55.185:9876;192.16.55.185:9877
brokerClusterName=ItcastCluster
brokerName=broker01
brokerId=0
deleteWhen=04
fileReservedTime=48
brokerRole=SYNC_MASTER
flushDiskType=ASYNC_FLUSH
brokerIP1=192.16.55.185
brokerIp2=192.16.55.185
listenPort=10911#创建第2个master broker
#master broker02
docker create --net host --name rmqbroker02 \
-e "JAVA_OPTS=-Duser.home=/opt" \
-e "JAVA_OPT_EXT=-server -Xms128m -Xmx128m -Xmn128m" \
-v /haoke/rmq/rmqbroker02/conf/broker.conf:/etc/rocketmq/broker.conf \
-v /haoke/rmq/rmqbroker02/logs:/opt/logs \
-v /haoke/rmq/rmqbroker02/store:/opt/store \
foxiswho/rocketmq:broker-4.5.2
#master broker02
namesrvAddr=192.16.55.185:9876;192.16.55.185:9877
brokerClusterName=ItcastCluster
brokerName=broker02
brokerId=0
deleteWhen=04
fileReservedTime=48
brokerRole=SYNC_MASTER
flushDiskType=ASYNC_FLUSH
brokerIP1=192.16.55.185
brokerIp2=192.16.55.185
listenPort=10811#创建第1个slave broker
#slave broker01
docker create --net host --name rmqbroker03 \
-e "JAVA_OPTS=-Duser.home=/opt" \
-e "JAVA_OPT_EXT=-server -Xms128m -Xmx128m -Xmn128m" \
-v /haoke/rmq/rmqbroker03/conf/broker.conf:/etc/rocketmq/broker.conf \
-v /haoke/rmq/rmqbroker03/logs:/opt/logs \
-v /haoke/rmq/rmqbroker03/store:/opt/store \
foxiswho/rocketmq:broker-4.5.2
#slave broker01
namesrvAddr=192.16.55.185:9876;192.16.55.185:9877
brokerClusterName=ItcastCluster
brokerName=broker01
brokerId=1
deleteWhen=04
fileReservedTime=48
brokerRole=SLAVE
flushDiskType=ASYNC_FLUSH
brokerIP1=192.16.55.185
brokerIp2=192.16.55.185
listenPort=10711#创建第2个slave broker
#slave broker01
docker create --net host --name rmqbroker04 \
-e "JAVA_OPTS=-Duser.home=/opt" \
-e "JAVA_OPT_EXT=-server -Xms128m -Xmx128m -Xmn128m" \
-v /haoke/rmq/rmqbroker04/conf/broker.conf:/etc/rocketmq/broker.conf \
-v /haoke/rmq/rmqbroker04/logs:/opt/logs \
-v /haoke/rmq/rmqbroker04/store:/opt/store \
foxiswho/rocketmq:broker-4.5.2
#slave broker02
namesrvAddr=192.16.55.185:9876;192.16.55.185:9877
brokerClusterName=ItcastCluster
brokerName=broker02
brokerId=1
deleteWhen=04
fileReservedTime=48
brokerRole=SLAVE
flushDiskType=ASYNC_FLUSH
brokerIP1=192.16.55.185
brokerIp2=192.16.55.185
listenPort=10611#启动容器
docker start rmqserver01 rmqserver02
docker start rmqbroker01 rmqbroker02 rmqbroker03 rmqbroker04

3. SprinBoot整合RocketMQ

3.1 导入依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.1.0.RELEASE</version></parent><groupId>cn.itcast.rocketmq</groupId><artifactId>itcast-rocketmq</artifactId><version>1.0-SNAPSHOT</version><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>org.apache.rocketmq</groupId><artifactId>rocketmq-spring-boot-starter</artifactId><version>2.0.0</version></dependency><dependency><groupId>org.apache.rocketmq</groupId><artifactId>rocketmq-client</artifactId><version>4.5.2</version></dependency></dependencies><build><plugins><!-- java编译插件 --><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><version>3.2</version><configuration><source>1.8</source><target>1.8</target><encoding>UTF-8</encoding></configuration></plugin></plugins></build>
</project>

说明：rocketmq-spring-boot-starter的依赖包是不能直接从中央仓库下载的，需要自己通过源码install到本地仓库的。
#源码地址（或者使用资料中的源码）
https://github.com/apache/rocketmq-spring
#进入源码目录，执行如下命令
mvn clean install

3.2 编写application.properties配置文件

# Spring boot application
spring.application.name = itcast-rocketmq
spring.rocketmq.nameServer=192.16.55.185:9876
spring.rocketmq.producer.group=my-group

3.3 生产者

import org.apache.rocketmq.spring.core.RocketMQTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class SpringProducer {@Autowiredprivate RocketMQTemplate rocketMQTemplate;/*** 发送消息** @param topic* @param msg*/public void sendMsg(String topic, String msg){this.rocketMQTemplate.convertAndSend(topic, msg);}
}

3.4 消费者

import org.apache.rocketmq.spring.annotation.RocketMQMessageListener;
import org.apache.rocketmq.spring.core.RocketMQListener;
import org.springframework.stereotype.Component;
@Component
@RocketMQMessageListener(topic = "my-topic",consumerGroup = "my-consumer",selectorExpression = "*")
public class SpringConsumer implements RocketMQListener<String> {@Overridepublic void onMessage(String msg) {System.out.println("接收到消息 -> " + msg);}
}

3.5 编写启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class MyApplication {public static void main(String[] args) {SpringApplication.run(MyApplication.class, args);}
}

3.6 测试代码

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@SpringBootTest
public class TestSpringRocketMQ {@Autowiredprivate SpringProducer springProducer;@Testpublic void testSendMsg(){this.springProducer.sendMsg("my-topic", "第一个Spring消息");}
}

3.7 事务消息

定义TransactionListenerImpl

import org.apache.rocketmq.spring.annotation.RocketMQTransactionListener;
import org.apache.rocketmq.spring.core.RocketMQLocalTransactionListener;
import org.apache.rocketmq.spring.core.RocketMQLocalTransactionState;
import org.apache.rocketmq.spring.support.RocketMQHeaders;
import org.springframework.messaging.Message;
import java.util.HashMap;
import java.util.Map;
@RocketMQTransactionListener(txProducerGroup = "myTransactionGroup")
public class TransactionListenerImpl implements RocketMQLocalTransactionListener {private static Map<String, RocketMQLocalTransactionState> STATE_MAP = new
HashMap<>();@Overridepublic RocketMQLocalTransactionState executeLocalTransaction(Message message,
Object o) {String transId =
(String)message.getHeaders().get(RocketMQHeaders.TRANSACTION_ID);try {System.out.println("执行操作1");Thread.sleep(500);System.out.println("执行操作2");Thread.sleep(800);STATE_MAP.put(transId, RocketMQLocalTransactionState.COMMIT);return RocketMQLocalTransactionState.COMMIT;} catch (Exception e) {e.printStackTrace();}STATE_MAP.put(transId, RocketMQLocalTransactionState.ROLLBACK);return RocketMQLocalTransactionState.ROLLBACK;}@Overridepublic RocketMQLocalTransactionState checkLocalTransaction(Message message) {String transId =
(String)message.getHeaders().get(RocketMQHeaders.TRANSACTION_ID);System.out.println("回查消息 -> transId = " + transId + ", state = " +
STATE_MAP.get(transId));return STATE_MAP.get(transId);}
}

生产者

import org.apache.rocketmq.spring.core.RocketMQTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Component;
import java.io.UnsupportedEncodingException;
@Component
public class SpringTransactionProducer {@Autowiredprivate RocketMQTemplate rocketMQTemplate;/*** 发送消息** @param topic* @param msg*/public void sendMsg(String topic, String msg) {Message message = MessageBuilder.withPayload(msg).build();// myTransactionGroup要和@RocketMQTransactionListener(txProducerGroup =
"myTransactionGroup")定义的一致this.rocketMQTemplate.sendMessageInTransaction("myTransactionGroup",topic,message,null);System.out.println("发送消息成功");}
}

消费者

import org.apache.rocketmq.spring.annotation.RocketMQMessageListener;
import org.apache.rocketmq.spring.core.RocketMQListener;
import org.springframework.stereotype.Component;
@Component
@RocketMQMessageListener(topic = "my-topic",consumerGroup = "my-consumer",selectorExpression = "*")
public class SpringConsumer implements RocketMQListener<String> {@Overridepublic void onMessage(String msg) {System.out.println("接收到消息 -> " + msg);}
}

测试用例

import cn.itcast.rocketmq.spring.transaction.SpringTransactionProducer;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@SpringBootTest
public class TestSpringRocketMQ {@Autowiredprivate SpringProducer springProducer;@Autowiredprivate SpringTransactionProducer springTransactionProducer;@Testpublic void testSendMsg(){this.springProducer.sendMsg("my-topic", "第2个Spring消息");}@Testpublic void testSendMsg2(){this.springTransactionProducer.sendMsg("my-topic", "第3个Spring消息");}
}